Latch bolt guard



Get. 11, 1949. w. L. GARBERDING LATCH BOLT GUARD Filed June 9, 1944 Waldo 'ariefdz'izg Patented Oct. 11, 1949 UNITED STATES PATENT orrics LATCH BOLT GUARD Waldo L. Garberding, Chicago, 111.

Application June 9, 1944, Serial No. 539,572

4 Claims. (01. 292346) This invention relates to improved latch bolt guards and more particularly concerns a device of this character which is adapted to be installed in such relation to the latch bolt of a door look as to prevent surreptitious opening of th door by retraction of the latch bolt by a fiat bladed instrumentality.

It is well known, of course, when the night latch is not thrown, that the ordinary door can easily be opened by slipping a fiat blade under or past the loosened or removed door stop and between the edge of the door and the door jarnb into abutment with the cam fac of the latch bolt which is then displaced by cammin it into retracted position by the thrust of the blade.

A principal aim of my invention is to provide an effective impediment to such surreptitious practice by the provision of a simple and inexpensive guard device which can be installed without the exercise of any particular skill and merely by following simpl unquestionable instructions,

with ordinary and customarily available simple tools such as a hammer and screw driver and without the need for any mortising or other alteration of the existing structure.

Another aim of the inventionis to provide a latch bolt guard which is adapted. to be manufactured by simple quantity production die forming methods of manufacture.

A further aim of the invention is to provide a novel latch bolt guard device which can be made from relatively thin sheet metal stock and which is yet quite strong and adequately resistant to deformation either when being installed or by tampering therewith after installation.

Among other aims of the invention is the provision of an effectual latch bolt guard which can neither be pried loose nor by-pa-ssed for surreptitious access to the latch bolt.

()ther advantages, objects and features of the invention will be readily apparent from the following description and from the accompanying one sheet of drawings in which:

Fig, 1 is a fragmentary horizontal sectional view through a door lock assembly showing a latch bolt guard embodying the features of my invention;

Fig. 2 is an elevational view of the door lock and showing the latch bolt guard;

Fig. 3 is a perspective view of the latch bolt guard; and

Fig. 4 is an enlarged fragmentary back elevational view of a slightly modified form of the latch bolt guard. r

In the drawing, the various features of the door structure and door lock are quite conventional, including as principal elements a door H] having a lock ll mounted in its swinging edge. The lock H is provided with a latch bolt [2 adapted to engage within a keeper opening IS in a keeper plate l4. mounted upon a conventionally constructed door jamb iii. A usual form of door stop moulding I! is carried by the door jamb outwardly beyond the keeper plate l4.

According to my invention, tampering accessibility to the latch bolt l2 by a flat instrumentality, such as a knife blade, spatula, saw blade, or the like, extended between or past the door jamb l5 and the loosened or removed door stop H and between the edge of the door and the iamb is quite effectually prevented by a novel latch bolt guard device l8. By preference, the guard device It is formed from relatively thin sheet material such as sheet steel which is thin enough to be received without any binding action in the customary operating clearance between the edge of the door and the door jamb, as well as between the face of the door and the door stop without requiring any alterations in the conventional disposition of the stop to accommodate the interposed thickness of the guard member. In practice, metal of about s thickness has been found Well adapted for the present purpose.

Despite the use of relatively thin material in the guard, adequate rigidity is attained by my particular construction, not only for resistance to deformation during installation of the device, but also for resisting tampering. Accordingly, the elongated body of the guard device is bent along a longitudinal line to provide mutually re-enforcing right-angular flanges 19 and 20. In this instance, the flange iii serves as a base to engage the door stop l5, and the flange 20 serves as a guard wing to lie adjacent to the inner or door opposing edge of the door stop 17 (Fig. 1). Thus, the door guard is adaptedto fit in the angle between the door jamb i5 and the door stop ll'and the adjacent edge of the door H3 is adapted to be received in the angle of the guard device.

In order to prevent the slipping of a tampering instrumentality under the base flange l 9, impeding means herein in the form of a series of prongs 24 is formed to extend beyond the jamb-opposing face of the base flange i9 into the door jar'nb I5. By preference the prongs?! are relatively narrow, enough so to facilitate driving into the jamb IE, but are wide enough and closely enough spaced to prevent the passage of a tampering instrumenta ity. By preference the prongs 2 I are struck out from the base flange i9 and extend integrally in the plane of the guard flange 2d. The apertures in the base flange 19 resulting from striking out of the prongs 2| account for but a minor proportion of the area of the base flange and are spaced substantially inwardly from the outer edge of the base flange so that the base flange thereby constitutes a solid bar of metal l9 outwardly of the tips of the apertures and a series of transverse bars IS'CeXtending from the solid marginal bar l9 to integral juncture with the stop-engaging flange 20 at the bases of the respective adjoining prongs 2 I. pattern of solid rigidifying base flange bars alternating with the prongs at the base of the stop-- engaging flange 20. The tips of the prongs are pointed while the sides for a substantial extent from the chamferin of the point to the bases of the prongs may be relatively straight as shown in Figs. 2 and 3. However, as shown in the modification of Fig. 4, the latch bolt guard device I8 may have prongs 2! which are slightly flared to provide shoulders 2! adjacent to the points thereof in order to attain adequate anchorage in the door jamb and resist any tendency toward squeezing out due to the resilient counter-thrust of the wood of the door jamb. After the guard device l8 or I8 has been completely formed, I preferably case harden it to attain greater rigidity and to render the flangesand the prongs for all practical purposes sawproof and drillproof.

By having the prongs 2| in the plane of the guard flange, driving force applied to the outer edge of the guard flange is directly effective to send the prongs into the door jamb. Where,

due to the thickness of the door stop if and the close proximity of the wing guard flange 20 thereto, insuflicient room is available for hammering against the edge of the flange 2%, a driving block such as indicated in broken outline at B in Fig. 3, may be set into the angle of the guard device to bear against the base flange [9 when setting the device. Then the prongs are guided straight into the jamb by engaging the wing flange 26 between the block B and edge of the door stop I1, and the block hammered to drive the prongs until the base flange i9 stops the driving progress by engaging the door jamb l5.

Although the prong-s afford substantial anchorage for the guard device, means are preferably provided for additionally positively securing the device to the door jamb. To this end. what would be the second prong from each end of the device is omitted, so as to leave a substantial uncut area which is provided with an aperture 22 for receiving a fastening element such as a screw 23 to secure the base flange l9 tightly against the door jamb. The fastening screws 23 then take the place of the respectively omitted prongs as tampering impediments. At the same time the prongs at the extremities of the device and the adjacent prongs of the series which flank the screw aperture areas of the base flange I9 serve to guard the fastening screws against access by such means as a saw blade.

Thus it will be apparent that I have provided a novel latch bolt guard which can be simply and easily installed in an existing doorway structure. Where the device is substantially centered with respect to the latch bolt aperture l3 and the latch bolt I 2, it fully obstructs every angle of approach to the latch bolt [2 from the direction of'the door stop H. In practice a length of about 5" in the guard device l8 has been found satisfactory with the flanges i8 and I9 about /2" wide. Uniform protection at each sideof the clearance This provides a substantially uniform.

4 space between the edge of the door and the door jamb within which the base flange I9 is accommodated, is assured by the full width of the guard flange 20 and the full length of the prongs 2| since the prongs are fully driven into the door jamb and held against dislodgement by the screws 23 as well as against being pried out by reason of the door edge opposing the base flange IS. The spacing between the prongs 2| is too narrow to admit passage of an instrument adequate to impart sufficient camming thrust to retract the latch bolt [2, assuming that it might be possible to force a very thin and very narrow blade under the base flange I 9. The latter can not be accomplished, however, if the guard device has been installed with just reasonable care because the base flange l9 abuts the door jamb I5 and the anchorage afforded by the prongs 2i and screws 23 stoutly resists any separation of the base flange. The guard flange 2E aifords adequate reenforcement to prevent bending of the base flange away from the jamb. Should it be endeavored to underpass the guard 58 by gouging out the wood back of the base flange l9, then the adjacent edge of the keeper plate i4 provides an impassable obstruction.

While the invention is susceptible of various modifications, and alternative constructions, I have shown in the drawings, and have herein described in detail a certain preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the following claims.

I claim:

1. In combination in a latch bolt guard, an elongated body of such length that when longitudinally centered with respect to the latch bolt of a closed door to be guarded the surreptitious ac cess to'the latch bolt with a tampering instrumentality from the outside is effectually prevented, said body being formed from relatively thin sheet metal bent longitudinally "into a coextensive pair of right-angularly related flanges, a series of relatively closely spaced prongs struck out from one of said flanges at substantially uniform intervals throughout the length thereof, with the exceptions to be mentioned, and extending in the plane of and in the opposite direction from the remaining flange so as to enable installing of the guard on the door jamb adjacent to the keeper plate for the latch bolt by striking against the edge of said remaining flange to drive the prongs into the door jamb, one prong adjacent to each opposite end of said one flange being omitted, and the prongless areas thus provided adjacent to each end of said one flange being formed with apertures to receive fastening elements adapted to be driven into the door jamb for supplementing the prongs in anchoring the device in place on the door jamb, the gaps left in the series of prongs being guarded by the respective prongs which are immediately adjacent each end of each prongless area to prevent tampering across to the fastening elements.

.2. In a latch bolt guard of the character described, an elongated member made of thin originally flat sheet metal, the metal being of such thinness as to be received freely within the normal operating clearance customarily provided between the edge of a door and the door jamb, said member being bent along a longitudinal line into substantially L-shape cross section and thereby having a pair of mutually reinforcing substantially right-angularly related flanges one of which is adapted to serve as a base flange to rest against the door jamb between the edge of an associated door and the door jamb and the other of which is adapted to rest against the door stop between the adjacent margin of the door and the door stop, with the adjacent corner of the door adapted to be freely received within the reentrant corner of the member formed by said flanges, and a series of individual co-operatively related attachment and guard prongs struck out from said base flange and extending at right angles thereto substantially in the plane of and parallel to the stopengaging flange whereby the prongs are adapted to be driven into the door jamb by hammering against the free edge of the stop-engaging flange or by applying driving force as by means of a driving block placed within the reentrant corner of the member and bearing against the base flange, the apertures in the base flange resulting from striking out of said prongs accounting for but a minor proportion of the area of said base flange and being spaced substantially inwardly from the outer edge of said base flange, said base flange therebyconstitutingasolid bar of metal outwardly of the tips of the apertures and a series of transverse bars extending from said solid marginal bar to integral juncture with the stop-engaging flange at the bases of the respective adjoining prongs, thus providing a substantially uniform pattern of solid rigidifying base flange bars alternating with said prongs at the base of the stop-engaging flange, the spaces between prongs being wide enough to permit free driving of the prongs into the door jamb but narrow enough to prevent the insertion therebetween of an instrumentality which would be effective to pry the bar loose or which might have a retracting effect upon the guarded latch bolt.

3. A latch bolt guard as defined in claim 1 in which the prongs are characterized by uniformity as to form from both faces in their plane and throughout their length to their tips so as to assure straight driving thereof into the door jamb.

4. A latch bolt guard as defined in claim 1 in which the prongs have slightly flared sides to anchor the prongs in the door jamb and counteract any tendency toward squeezing of the prongs from the door jamb due to the resilient pressure of the wood of the jamb after the prongs are driven thereinto.

WALDO L. GARBERDING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,579,139 Phillips Mar. 30, 1926 1,618,846 Rippien Feb. 22, 1927 1,863,487 Kirkpatrick June 14, 1932 2,041,625 Schmidt May 19, 1936 2,255,860 Riedel Sept. 16, 1941 FOREIGN PATENTS Number Country Date 3,072-31 Australia Dec. 21, 1931 374,916 Great Britain June 9, 1932 491,285 Great Britain Aug. 30, 1938 Certificate of Correction Patent No. 2,484,024 October 11, 1949 WALDO L. GARBERDING It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 67, for the word across read access; column 6, lines 5 and 10 respectively, for the claim reference numeral 1 read 2;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 7th day of March, A. D. 1950.

THOMAS F. MURPHY,

Assistant Gammz'sgz'oner of Patents. 

